Methods of selectively forming a material using a parylene coating and related semiconductor structures

ABSTRACT

Methods for depositing a material, such as a metal or a transition metal oxide, using an ALD (atomic layer deposition) process and resulting structures are disclosed. Such methods include treating a surface of a semiconductor structure periodically throughout the ALD process to regenerate a blocking material or to coat a blocking material that enables selective deposition of the material on a surface of a substrate. The surface treatment may reactivate a surface of the substrate toward the blocking material, may restore the blocking material after degradation occurs during the ALD process, and/or may coat the blocking material to prevent further degradation during the ALD process. For example, the surface treatment may be applied after performing one or more ALD cycles. Accordingly, the presently disclosed methods enable in situ restoration of blocking materials in ALD process that are generally incompatible with the blocking material and also enables selective deposition in recessed structures.

CROSS-REFERENCE TO RELATED APPLICATION

This application is a continuation of U.S. patent application Ser. No.12/872,608, filed Aug. 31, 2010, pending, the disclosure of which ishereby incorporated herein in its entirety by this reference.

TECHNICAL FIELD

The invention, in various embodiments, relates generally to methods forperforming atomic layer deposition (ALD). More particularly, thisdisclosure relates to methods of performing area-selective ALD.

BACKGROUND

ALD processes are used to produce thin, conformal films having highthickness accuracy and step coverage. ALD utilizes a series ofsequential, self-limiting surface reactions, each forming a monolayer ofadsorbed precursor, to form the film. ALD provides atomic layer controland enables the films to be deposited on structures having high aspectratios. ALD conventionally uses two or more gaseous precursors, eachbeing sequentially introduced into a reaction chamber. A wide variety ofmaterials may be deposited by ALD, many of which are used in thefabrication of semiconductor devices and integrated circuits (ICs).

In a conventional ALD process, at least one precursor is introduced to asubstrate in a reaction chamber in alternate pulses separated by inertgas purging (in flow type reactors) or by evacuation of the reactor (inhigh-vacuum type reactors). The precursors react with surface groups onthe substrate, or chemisorb on exposed surfaces of the substrate. Theinert gas may then be flowed into the reaction chamber to substantiallyremove the precursor from the chamber before introducing anotherprecursor.

The possibility of altering functional groups on surfaces of substrates,such as silicon substrates, enables selective deposition of materials onthe substrate by ALD. For example, surface treatments may be used toincrease reactivity of the surface of the substrate or to blockdeposition on regions of the surface of the substrate. Exposed regionsof a patterned surface of the substrate may be selectively treated toyield reactive surface regions including reactive functional groups,such as, organic terminal groups, that improve nucleation of theprecursors during the ALD process.

One example of selective deposition of materials using an ALD process isthe patterning of hafnium dioxide (HfO₂) on silicon using a blockingchemistry that involves siloxane attachment of compounds to surfaces ofsilicon dioxide (SiO₂). For example, the silicon dioxide may bedeposited on the silicon using conventional techniques and, thereafter,conventional lithographic techniques may be used to pattern the silicondioxide so that areas of the silicon are exposed through the silicondioxide. Surfaces of the silicon dioxide may be exposed tooctadecyltrichlorosilane (ODTS) to form an octadecyltrichlorosilanemonolayer on the surfaces of the silicon dioxide. An ALD process maythen be performed to selectively form the hafnium oxide on the silicon,without the hafnium oxide forming on the octadecyltrichlorosilanemonolayer overlying the silicon dioxide.

Selective deposition of materials using an ALD process has also beendemonstrated using a patterned organic material. For example, platinum(Pt) may be selectively deposited on silicon by an ALD process using1-octadecene as a blocking material. Silicon dioxide is deposited andpatterned over the silicon using conventional techniques. The1-octadecene may be adsorbed to the silicon exposed through the silicondioxide to form a patterned surface including nonreactive organicregions (i.e., 1-octadecene regions) and reactive cleared regions (i.e.,regions of exposed silicon). An ALD process may be performed toselectively deposit the platinum over the exposed silicon regionswithout the platinum depositing on the 1-octadecene regions.

However, the ability to pattern organic materials using conventionallithographic techniques is limited since it is only possible to alterfunctional groups or deposit materials on horizontal surfaces of thesubstrate, not on surfaces of recessed structures in the substrate.Furthermore, conventional blocking materials are often not compatiblewith conventional ALD processes. For example, platinum deposition usinga conventional ALD process is performed at temperatures of greater thanor equal to 300° C. and may use oxygen as a reactant. Under suchconditions, conventional surface treatments may be damaged, degraded orremoved from the surface of the substrate, especially during ALDprocesses having longer cycle times, which are used to deposit increasedthicknesses of material. For instance, rapid degradation ofself-assembled monolayers, such as octadecyltrichlorosilane andalkanethiol monolayers, during ALD processes has been observed. SeeTatoulian et al., “Plasma Surface Modification of Organic Materials:Comparison between Polyethylene Films and OctadecyltrichlorosilaneSelf-Assembled Monolayers,” Langmuir, 20, 10481 (2004); Xue and Yang,“Chemical Modifications of Inert Organic Monolayers with Oxygen Plasmafor Biosensor Applications,” Langmuir, 23, 5831 (2007); Raiber et al.,“Removal of Self-Assembled Monolayers of Alkanethiolates on Gold byPlasma Cleaning,” Surf. Sci., 595, 56 (2005); Park et al., “MicrocontactPatterning of Ruthenium Gate Electrodes by Selective Area Atomic LayerDeposition,” App. Phys. Lett., 86, 051903 (2005); and Lee et al.,“Degradation of the Deposition Blocking Layer During Area-SelectivePlasma-Enhanced Atomic Layer Deposition of Cobalt,” Journal of theKorean Physical Society, 56, 1 (2010).

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a flow diagram illustrating an atomic layer deposition (ALD)process according to an embodiment of the present invention; and

FIGS. 2A through 3B are cross-sectional views of work pieces formedaccording to embodiments of the present invention.

DETAILED DESCRIPTION

The illustrations presented herein are not meant to be actual views ofany particular component, device, or system, but are merely idealizedrepresentations that are employed to describe embodiments of the presentinvention.

As used herein, the terms “atomic layer deposition” and “ALD” mean andinclude a deposition process in which a plurality of consecutivedeposition cycles is conducted in a reaction chamber or a depositionchamber.

As used herein, the term “ALD process” means and includes a process offorming a material using ALD and the term “ALD material” means andincludes a material formed by an ALD process.

As used herein, the term “ALD cycle” means and includes sequentiallyintroducing each precursor into a reaction chamber or a depositionchamber separately followed by pumping/purging the reaction chamber orthe deposition chamber with an inert gas to prevent mixing or reactingof the precursors.

As used herein, the term “substrate” means and includes a base materialor construction upon which materials, such as the ALD material, areformed. The substrate may be a semiconductor substrate, a basesemiconductor layer on a supporting structure, a metal electrode or asemiconductor substrate having one or more layers, structures or regionsformed thereon. The substrate may be a conventional silicon substrate orother bulk substrate comprising a layer of semiconductive material. Asused herein, the term “bulk substrate” means and includes not onlysilicon wafers, but also silicon-on-insulator (“SOI”) substrates, suchas silicon-on-sapphire (“SOS”) substrates or silicon-on-glass (“SOG”)substrates, epitaxial layers of silicon on a base semiconductorfoundation or other semiconductor or optoelectronic materials, such assilicon-germanium (Si_(1-x)Ge_(x) ), germanium (Ge), gallium arsenide(GaAs), gallium nitride (GaN), or indium phosphide (InP).

Methods for selectively depositing an ALD material on the substrate withrespect to a blocking material using an atomic layer deposition (ALD)process are disclosed. For example, a blocking material may be formedover portions of a substrate or an inteimediate material to preventdeposition of the ALD material on regions of the substrate or theintermediate material underlying the blocking material. Accordingly, theALD process may be performed to selectively deposit the ALD material onsurfaces of the substrate exposed through the blocking material. ThisALD process is commonly referred to in the art as an “area-selectiveALD” process. The ALD material selectively deposited on the substratewith respect to the blocking material may be any material that may beselectively deposited by ALD, such as a metal, a metal oxide, a metalnitride or a perovskite. The methods include performing at least onesurface treatment on the blocking material between one or more ALDcycles. During the ALD process, the blocking material may be exposed toat least one of increased temperature and oxidizing gases that maydamage or degrade the blocking material. The damaged or degradedblocking material may be rendered inoperable for the purpose ofpreventing formation of the ALD material during the ALD process, thus,resulting in the formation of the ALD material on undesired regions ofthe substrate. A surface treatment may be performed to restore or coatthe blocking material periodically throughout the ALD process, enablingselective deposition of a greater thickness of the ALD material thanachievable using conventional processes. The methods may additionallyinclude reactivating a surface of the substrate or intermediate materialtoward the blocking material to facilitate regeneration of the blockingmaterial. For example, the surface treatment may be applied afterperforming at least one ALD cycle during the ALD process. Accordingly,in situ regeneration of the blocking material enables continuedselective deposition of the ALD material by the ALD process that mayotherwise be incompatible with such blocking materials. Furthermore, thepresently disclosed methods enable selective deposition of materials byALD in recessed structures, as will be described.

Metals, such as platinum (Pt), silver (Ag), gold (Au), ruthenium (Ru),rhodium (Rh), palladium (Pd), osmium (Os) and iridium (Ir), aluminum(Al), titanium (Ti), zirconium (Zr), hafnium (Hf), tantalum (Ta), andtungsten (W), and oxides of such metals may be produced by the ALDprocesses. Metal oxides, such as hafnium oxide (HfO₂), zirconium oxide(ZrO₂), aluminum oxide (Al₂O₃) and zinc oxide (ZnO), are widely used in,for example, microelectronics, opto-electronics, ceramics, gas sensorsand catalysts. Noble metals, such as platinum (Pt), are chemicallystable and generally withstand oxidizing conditions. Therefore, noblemetals are useful in integrated circuits (ICs) as electrodes in dynamicrandom access memories (DRAMs) and ferroelectric random access memories(FRAMs). For example, platinum has enormous application prospects in ICsdue to its chemical stability and excellent electrical properties.Perovskites, such as barium strontium titanate (Ba_(1-x)Sr_(x)TiO₃, BST)and lead zirconate titanate ((Pb[Zr_(x)Ti_(1-x)]O₃, PZT), may also beproduced by ALD processes. Perovskites are used in a variety ofapplications, such as for ferroelectric, dielectric, pyroelectric, orpiezoelectric optoelectronic components. Metals, metal oxides, metalnitrides and perovskites may be deposited using ALD processes. Suchmetals and compounds are listed only as representative examples for thesake of clarity. The presently disclosed methods may be used to performany ALD process.

Perovskites are becoming increasingly important as a material forresistive memory electrodes. Since dry etching and patterning of theperovskites can be challenging, the selective deposition processdescribed herein provides distinct advantages for fabrication ofresistive memory. In addition, precursors of the perovskites that do notreact during ALD processes may be recovered in their original precursorform. Selective deposition of perovskites involves reaction of theprecursors only at desired locations, thus increasing recovery ofunreacted precursors and reducing deposition costs.

The following description provides specific details, such as materialtypes, material thicknesses and processing conditions in order toprovide a thorough description of embodiments of the invention. However,a person of ordinary skill in the art will understand that theembodiments of the invention may be practiced without employing thesespecific details. Indeed, the embodiments of the invention may bepracticed in conjunction with conventional semiconductor fabricationtechniques employed in the industry.

Unless the context indicates otherwise, the materials described hereinmay be formed by any suitable technique including, but not limited to,spin coating, blanket coating, chemical vapor deposition (“CVD”), atomiclayer deposition (“ALD”), plasma enhanced ALD, or physical vapordeposition (“PVD”). Alternatively, the materials may be grown in situ.Depending on the specific material to be formed, the technique fordepositing or growing the material may be selected by a person ofordinary skill in the art.

FIG. 1 is a flow diagram illustrating an embodiment of a method ofselectively forming an ALD material on a substrate by an ALD process100. For example, a work piece may be formed that includes a blockingmaterial overlying at least one region of the substrate. In someembodiments, the blocking material may be formed on a silicon substrateby attachment to terminal hydride groups on the regions of substrate. Inother embodiments, the blocking material may be formed on an oxidematerial (i.e., the intermediate material) overlying the substrate byattachment to terminal hydroxide groups on the regions of the substrate.

The blocking material may be formed over surfaces of the substrate toprevent the ALD material from forming on such surfaces during the ALDprocess 100. In some embodiments, the blocking material may be formed onselected surfaces of the substrate using conventional deposition andpatterning techniques, which are not described in detail herein. Inother embodiments, the blocking material may be formed on surfaces of anintermediate material, such as a dielectric material, overlying selectedsurfaces of the substrate by conventional deposition and patterningtechniques, which are not described in detail herein. For example, theblocking material may comprise an organic material, such as, aphotoresist material, a vapor deposited polymer, an alkylchlorosilanematerial (e.g., octadecyltrichlorosilane (ODTS), dodecyltrichlorosilane,and trimethylchlorosilane), a chloroalkyl, a chloroalkene, a 1-alkene ora 1-alkyne.

During the ALD process 100, the blocking material may prevent formationof the ALD material on regions of the substrate underlying the blockingmaterial so that the ALD material is selectively formed on surfaces ofthe substrate exposed through the blocking material. The ALD process 100may include performing one or more ALD cycles 102 to form the ALDmaterial or a portion of the ALD material over regions of a substratenot in contact with the blocking material, optionally performing anactivation treatment 104 to restore reactivity of the substrate to theblocking material and performing a surface treatment 106 to regeneratethe blocking material overlying the substrate. In some embodiments, theblocking material may be degraded during a plurality of ALD cycles 102and the activation treatment 104 and/or the surface treatment 106 may beperformed after the plurality of ALD cycles 102 to restore or coat theblocking material. For example, the activation treatment 104 may includecleaning the surfaces of the substrate with a vapor phase treatment,such as ozone (O₃) or hydrofluoric acid (HF) to restore reactivity ofthe substrate or the intermediate material toward the blocking material.The substrate may be formed from any material on which ALD may beperformed, such as, a semiconductor substrate, an oxide material, aglass material or a metalized polymer. The blocking material mayinclude, for example, a resist material, an alkylchlorosilane material,a chloroalkyl material, a 1-alkene, a 1-alkyl, a fluorinated alkyl or afluorinated polymer. In embodiments in which the blocking materialincludes a 1-alkene and a 1-alkyl, the blocking material may includeless than about 20 carbon atoms.

The ALD cycle(s) 102 may be performed to form a first thickness of theALD material on the surfaces of the substrate exposed through theblocking material. As a non-limiting example, the ALD material mayinclude platinum, hafnium oxide, copper, titanium dioxide (TiO₂), nickel(Ni), molybdenum (Mo), zinc sulfide (ZnS), gallium arsenide, indiumphosphide, tin dioxide (SnO₂), magnesium oxide (MgO₂), nickel oxide(NiO, Ni₂O₃), iridium, ruthenium, iridium dioxide (IrO₂), rutheniumoxide (RuO₂, RuO₄), barium strontium titanate (Ba_(1-x)Sr_(x)TiO₃, BST),lead zirconate titanate ((Pb[Zr_(x)Ti _(1-x)]O₃, PZT),germanium-antimony-tellurium (Ge₂Sb₂Te₂, GST), germanium sulfide (GeS),copper telluride (CuTe).

To deposit the ALD material on exposed portions of the substrate, thework piece may be placed into a reaction chamber (or may remain in thereaction chamber from previous processing) and, in a first reaction ofthe ALD process, a precursor may be introduced into the reaction chamberand may chemisorb to surfaces of the substrate exposed through theblocking material. The precursor may include any compound that exhibitssufficient volatility and sufficiently adsorbs onto or reacts with thesurface of the substrate. The precursor supplied to the reaction chambermay be selected such that an amount of precursor that may be bound tothe substrate surface is determined by the number of available bindingsites and by the physical size of the chemisorbed species (includingligands) and such that these sites are fully saturated. The precursormay be introduced into the reaction chamber for an amount of timesufficient for the adsorption or reaction to occur, such as from about0.1 second to about 30 seconds. For example, the precursor may beintroduced into the reaction chamber at a flow rate of between about 0.1sccm and about 10 sccm, a temperature of between about 100° C. and about400° C., and a pressure of between about 0.0005 Torr and about 1 Torr. Afirst monolayer of the precursor may be formed on the surface of thesubstrate as the precursor is chemisorbed on the surface of substrate.The first monolayer formed by chemisorption of the precursor may beself-terminated since a surface of the first monolayer may benon-reactive with the precursor used in forming the first monolayer.

Examples of suitable ALD precursors include, but are not limited to, atleast one of a metal alkyl, a metal alkyl amide, a metal alkoxide, ametal beta-diketonate, an organometallic compound, a metal carbonyl anda fluorinated self-assembled monolayer structure (SAM). Alkyl groupswithin the precursors may include, for example, ethyl, ethyl, isopropyl,propyl, butyl, tert-butyl. Examples of suitable ALD precursors include,but are not limited to, an aluminum-containing precursor, such asaluminum ethoxide (Al(OC₂H₅)₃), aluminum hexafluoroacetylacetonate(Al(CF₃COCHCOCF₃)₃) and trimethylaluminum ((CH₃)₃Al); abarium-containing precursor, such asbis(n-propyltetramethylcyclopentadienyl)barium (Ba[(C₃H₇)(CH₃)₄C₅]₂); acopper-containing precursor, such as copper(II) trifluoroacetylacetonate(Cu(CF₃COCHCOCH₃)₂) and copper(II) trifluoroacetylacetonate((C₅H₅)CuP(C₂H₅)₃); a gallium-containing precursor, such astriethylgallium; a hafnium-containing precursor, such asbis(cyclopentadienyl)dimethylhafnium ((C₅H₅)₂Hf(CH₃)₂) andtetrakis(dimethylamino)hafnium (Hf(N(CH₃)₂)₄); an iridium-containingprecursor, such as CH₃CpIr(CO)₃; a lead-containing precursor; anickel-containing precursor, such as nickel oxide (NiO) andbis(cyclopentadienyl) nickel ((C₅H₅)₂Ni); an oxygen-containingprecursor, such as water (H₂O) and oxygen (O₂); a platinum-containingprecursor, such as (trimethyl)methylcyclopentadienylplatinum(IV)((CH₃)₃(CH₃C₅H₄)Pt); a ruthenium-containing precursor, such asbis(cyclopentadienyl)ruthenium ((C₅H₅)₂Ru); a silicon-containingprecursor, such as a hydride or a silane (e.g., hexachlorodisilane (HCD,Si₂Cl₆) dichlorosilane (DCS, SiH₂Cl₂), silane (SiH₄), disilane(H₃SiSiH₃), trichlorosilane (TCS, SiHCl₃); a strontium-containingprecursor; a tantalum-containing precursor, such as tantalum(V)methoxide (Ta(OCH₃)₅) and pentakis(dimethylamino)tantalum(V)(Ta[N(CH₃)₂]₅); a titanium-containing precursor, such astetrachlorodiaminetitanium(IV) (TiCl₄(NH₃)₂),tetrakis(diethylamino)titanium (Ti[N(C₂H₅)₂]₄) and titanium(IV) ethoxide(Ti(OC₂H₅)₄); a tungsten-containing precursor, such as mesitylenetungsten tricarbonyl (C₉H₁₂W(CO)₃); a zirconium-containing precursor,such as bis(cyclopentadienyl)dimethylzirconium ((C₅H₅)₂Zr(CH₃)₂),tetrakis(diethylamino)zirconium (Zr[N(CH₂CH₃)₂]₄); and any othercompound suitable for use as a precursor in an ALD process.

Subsequent pulsing with an inert gas removes excess precursor from thereaction chamber, specifically the precursor that has not chemisorbed tothe surface of the substrate. The inert gas may be nitrogen (N₂), argon(Ar), helium (He), neon (Ne), krypton (Kr), xenon (Xe), or other gasesthat, although not inert, behave as inert under the conditions of thespecific deposition. Purging the reaction chamber also removes volatileby-products produced during the ALD process. In one embodiment, theinert gas may be nitrogen (N₂). The inert gas may be introduced into thereaction chamber, for example, for from about 5 seconds to about 120seconds. After purging, the reaction chamber may be evacuated or“pumped” to remove gases, such as excess precursor or volatileby-products. For example, the precursor may be purged from the reactionchamber by techniques including, but not limited to, contacting thesubstrate with the inert gas and/or lowering the pressure in thereaction chamber to below the deposition pressure of the precursor toreduce the concentration of the precursor contacting the substrateand/or chemisorbed species. Additionally, purging may include contactingthe first monolayer with any substance that allows chemisorptionby-products to desorb and reduces the concentration of the precursorbefore re-introducing the precursor or introducing another precursor. Asuitable amount of purging to remove the excess precursor and thevolatile by-products may be determined experimentally, as known to thoseof ordinary skill in the art. The pump and purge sequences may berepeated multiple times. The pump and purge sequences may start or endwith either the pump or purge act. The time and parameters, such as gasflow, pressure and temperature, during the pump and purge acts may bealtered during the pump and purge sequence.

Another reaction of the ALD process 100 includes re-introducing theprecursor or introducing another, different precursor into the reactionchamber to form a second monolayer over the first monolayer. Dependingon the ALD material to be formed, suitable precursors for forming theALD material may be selected by a person of ordinary skill in the art.The second monolayer and the first monolayer may be reacted to form adesired ALD material. Reaction by-products and excess precursor may beremoved from the reaction chamber by using the pump and purge sequenceas described above. For example, a purge may be performed by introducingthe inert gas into the reaction chamber. Conventionally, precursor pulsetimes range from about 0.5 second to about 30 seconds. A desiredthickness of the ALD material may be deposited on the substrate throughmultiple, repetitious ALD cycles 102, where each ALD cycle 102 depositsa monolayer of material.

During the ALD cycles 102, the blocking material on the work piece maybe exposed to increased temperatures and oxidizing gases, or reactivegases, that may degrade or deteriorate the blocking material. Suchconditions may, additionally, decrease surface reactivity between thesubstrate or the intermediate material and the blocking material,causing detachment of the blocking material from the underlying material(i.e., the substrate or the intermediate material). For example, afterdepositing a first thickness of the ALD material on the substrate,degradation of the blocking material and/or reduced surface reactivitybetween the substrate and the blocking material may impede selectivedeposition of the ALD material with respect to the blocking material.Accordingly, the thickness of the ALD material may be limited by thenumber of ALD cycles 102 that may be performed before the blockingmaterial begins to degrade, as will be described. The surface treatment106 and, optionally, the activation treatment 104 may be performed toregenerate the blocking material over desired regions of the substrate.The activation treatment 104, if utilized, may include, for example,cleaning a surface of a substrate and, thereafter, optionally treatingthe surface of the substrate or the intermediate material to restorereactivity with the blocking material. The surface treatment 106 mayinclude introducing at least one organic material to the substrate andremaining portions of the blocking material to regenerate or rebuild theblocking material. The activation treatment 104 and the surfacetreatment 106 may be performed in situ in the reaction chamber or may beperformed ex situ. The activation treatment 104 and the surfacetreatment 106 described herein are not limited to any particular ALDprocess and may be used in combination with any ALD process known in theart wherein the ALD material is selectively deposited with respect to ablocking material. The activation treatment 104 and the surfacetreatment 106 are also not limited to ALD processes including anyparticular number of ALD cycles 102 and may be performed duringdeposition processes including any number of ALD cycles 102, or after asingle ALD cycle, used to form the ALD material.

By restoring the blocking material that overlies regions of thesubstrate, the area-selective formation of increased thicknesses of ALDmaterial and, furthermore, enables deposition of ALD material withinrecessed regions. Specifically, the blocking material may be formed oversidewalls of recessed regions preventing deposition of ALD materialthereon and enabling selective deposition of ALD material on surfacesexposed by the recessed regions (i.e., bottom surfaces of the recessedregions).

FIG. 2A depicts a work piece 200 that includes a substrate 202, amaterial 204, e.g., a dielectric material, over portions of a surface ofthe substrate 202 and a blocking material 208 over an intermediatematerial, such as material 204. As a non-limiting example, the substrate202 may be a doped or undoped silicon material. The material 204 may bea silicon dioxide material formed by a technique known in the art, suchas, for example, atomic layer deposition (ALD), chemical vapordeposition (CVD), or plasma vapor deposition (PVD). For example, thematerial 204 may have a thickness of between about 20 nm and about 500nm. To produce the work piece 200 illustrated in FIG. 2A, the material204 may be formed over the surface of the substrate 202 and a pluralityof recesses 206 may be formed in the material 204 using, for example, aconventional reactive ion etching (RIE) process. For simplicity, thework piece 200 is depicted with two recesses 206 in the material 204.However, the material 204 may include any number of recesses 206, or asingle recess 206.

The blocking material 208 may be formed on sidewalls and horizontalsurfaces of the material 204 without being formed on surfaces of thesubstrate 202 such that the portions of the substrate 202 are exposedthrough the material 204 and the blocking material 208. For example, theblocking material 208 may be formed from an organic material thatexhibits reactivity or affinity toward the material 204, such as ahydroxide terminated silane compound that forms a self-assembledmonolayer (SAM). The blocking material 208 may be formed by depositing aphotoresist, a vapor deposited polymer, or an alkylchlorosilanematerial, such as octadecyltrichlorosilane (ODTS),dodecyltrichlorosilane, trimethylchlorosilane andtridecafluoro-1,1,2,2-tetrahydrooctyltrichloro-silane (FOTS), which mayself-assemble to form a continuous film over the material 204. Forexample, the blocking material 208 may be formed by exposing the surfaceof the work piece 200 (i.e., exposed surfaces of the substrate 202) tothe alkylchlorosilane material under conditions in which thealkylchlorosilane material interacts with the material 204 to form theblocking material 208. As a non-limiting example, the material 204 maybe formed from silicon dioxide and the blocking material 208 may beformed by exposing the surface of the work piece 200 tooctadecyltrichlorosilane so that the octadecyltrichlorosilane reactswith the exposed surfaces of the material 204 to form a self-assembledsiloxane monolayer over the material 204. Optionally, the surfaces ofthe material 204 may be prepared by at least one of cleaning and etchingprior to forming the blocking material 208 thereon.

An ALD material 210 may be formed in the recesses 206 of the substrate202 using the ALD process 100 described with respect to FIG. 1. Duringthe ALD process 100, the blocking material 208 may prevent deposition ofthe ALD material 210 thereon. A first thickness D1 of the ALD material210 may be formed on the exposed surfaces of the substrate 202 using atleast one ALD cycle 102 (FIG. 1). For example, between about 5 ALDcycles and about 100 ALD cycles 102 may be performed to form the firstthickness D1 of the ALD material 210. By way of example and notlimitation, the blocking material 208 may be formed fromoctadecyltrichlorosilane, the ALD material 210 may be formed fromplatinum and between about 50 ALD cycles and about 100 ALD cycles 102may be performed so that the first thickness D1 of the platinum is lessthan or equal to about 25 Å. In one embodiment, about 75 ALD cycles 102are conducted to form the first thickness D1 of the platinum. As theblocking material 208 becomes damaged or degraded during the ALD cycles102, the ALD material 210 may be undesirably formed on surfaces of thematerial 204 exposed by the degradation of the blocking material 208.Thus, the first thickness D1 of the ALD material 210 may be limited bythe number of ALD cycles 102 that may be performed before the blockingmaterial 208 is damaged or degraded.

The surface treatment 106 (FIG. 1) and, optionally, the activationtreatment 104 (FIG. 1) may be performed to restore the blocking material208 on the material 204 or to coat the remaining portions of theblocking material 208 and/or regions of the material 204 exposed bydegradation of the blocking material 208. Optionally, the activationtreatment 104 may be performed to increase the reactivity of the surfaceof the material 204 toward the blocking material 208. In someembodiments, the activation treatment 104 may be performed in situ withthe ALD process 100 (FIG. 1) by exposing the work piece 200 to at leastone activating agent in the reaction chamber after performing the ALDcycle(s) 102 (FIG. 1). In some embodiments, the activating agent may beintroduced to the work piece 200 by bubbling an inert gas (i.e.,nitrogen gas) through an aqueous hydrofluoric acid (HF) solution (i.e.,49% hydrofluoric acid in water) at a volume flow rate of from about 0.1liter/minute to about 1 liter/minute for a duration of from about 1minute to about 20 minutes. In other embodiments, the work piece 200 maybe exposed to ozone at a flow rate of from about 1 slm to about 10 slmfor a duration of from about 1 minute to about 5 minutes. In yet furtherembodiments, the work piece 200 may be removed from the reaction chamberand the activation treatment 104 may be performed ex situ.

In some embodiments, the surface treatment 106 of the ALD process 100may be performed to reform the blocking material 208 on the regions ofthe material 204 (FIG. 2B) where the blocking material 208 may have beendamaged or degraded during the ALD cycle(s) 102 (FIG. 1). For example,the surface treatment 106 may include exposing the work piece 200 to anorganic material that reacts with exposed surfaces of the material 204and remaining portions of the blocking material 208 to restore theblocking material 208. For example, the blocking material 208 mayinclude a polymer material and the organic material may include acarboxylic acid (e.g., acrylic acid), which carboxylic acid may begrafted to remaining portions of the blocking material 208. For example,the blocking material 208 may comprise polyethylene or polystyrene and asolution of acrylic acid and benzophenone in a solvent, such as acetone,may be supplied into the reaction chamber in the vapor phase to initiategrafting of the acrylic acid to the blocking material 208 and/or exposedsurfaces of the material 204 without being deposited on the ALD material210.

In other embodiments, the surface treatment 106 may be performed to coatthe blocking material 208 to prevent damage or degradation to theblocking material 208 during the ALD cycle(s) 102. After forming athickness (e.g., the first thickness D1) of the ALD material 210 usingthe ALD cycle(s), the surface treatment 106 may be performed to form acoating 212 (shown in broken lines) over exposed surfaces of thematerial 204 and/or remaining portions of the blocking material 208selective to the ALD material 210. For example, the surface treatment106 may include exposing the work piece 200 to a polymer material thatpolymerizes on exposed surfaces of the material 204 and/or remainingportions of the blocking material 208 to form a coating 212 (shown inbroken lines) over the blocking material 208. The ALD material 210 mayinhibit deposition of the polymer material over the ALD material 210such that the coating 212 does not form over the ALD material 210. Forexample, the polymer material may include a parylene, such as asubstituted [2.2]paracyclophane, and the blocking material 208 may becoated by exposing the blocking material 208 to the organic material ina sublimated or vapor state. The ALD material 210 may include a materialthat inhibits deposition of the polymer material, such as, platinum,gold, silver, nickel, copper, iridium, tungsten, tantalum and titanium.For example, the polymer material may be sublimated at a temperature offrom about 75° C. to about 150° C. and introduced into the reactionchamber such that the polymer material polymerizes on the exposedsurfaces of the material 204 and/or remaining portions of the blockingmaterial 208 without polymerizing on the ALD material 210 to form thecoating 212. The coating 212 may protect the blocking material 208 fromfurther damage or degradation or may replace degraded or damaged regionsof the blocking material 208.

The blocking material 208 may be restored or coated in situ byintroducing the organic material to the work piece 200 in the reactionchamber after performing the ALD cycle(s) 102 (FIG. 1). In otherembodiments, the work piece 200 may be removed from the reaction chamberand the organic material may be deposited on the exposed surfaces of thematerial 204 and remaining portions of the blocking material 208 using,for example, a conventional chemical vapor deposition (CVD) process. Forexample, if the blocking material 208 comprises a hydroxide terminatedsilane compound, the work piece 200 may be exposed to a vapor containingoctadecyltrichlorosilane so that the octadecyltrichlorosilane reactswith the exposed surfaces of the material 204 and remaining portions ofthe blocking material 208. As the octadecyltrichlorosilane in the vaporcontacts the exposed surfaces of the material 204 and remaining portionsof the blocking material 208, a self-assembled monolayer of the blockingmaterial 208 may form over the material 204. As indicated by arrow 108,and as shown in FIG. 1, the activation treatment 104 and the surfacetreatment 106 may be repeated any number of times in order to restore orcoat the blocking material 208 overlying the material 204.

After regenerating the blocking material 208 over the material 204 onthe work piece 200, one or more additional ALD cycles 102 (FIG. 1) maybe performed, as indicated by arrow 110 (FIG. 1), to form a secondthickness D2 of the ALD material 210 over the first thickness D1 of theALD material 210. The ALD cycle(s) 102, the activation treatment 104 andthe surface treatment 106 may be repeated to form a desired thickness ofthe ALD material 210 on the substrate 202. By periodically performingthe optional activation treatment 104 and the surface treatment 106between the ALD cycles 102 to restore or coat the blocking material 208,the ALD material 210 having an increased thickness may be formed incomparison to the thickness formed using conventional area-selective ALDprocesses. For simplicity, the ALD material 210 is illustrated in FIG. 2as including two thicknesses (i.e., the first and second thicknesses D1and D2). However, any number of thicknesses of the ALD material 210 maybe formed using the disclosed methods. The blocking material 208 may bedamaged, degraded or removed during the ALD cycle(s) 102 as thethickness of the ALD material 210 increases. Conventional area-selectiveALD processes may, therefore, be inadequate for forming the ALD materialin recessed regions having greater depths (e.g., about 200 Å).Optionally performing the surface treatment 106 and the activationtreatment 104 between one or more ALD cycles 102 to restore or coat theblocking material 208 during the ALD process 100 (FIG. 1), thus, enablesarea-selective deposition of the ALD material 210 in recessed regions,such as recesses 206.

FIG. 3A depicts a work piece 300 that includes a substrate 302 having ablocking material 308 formed over portions of a surface of the substrate302. For example, the blocking material 308 may be formed from anorganic material, such as an amphiphilic material, that exhibitsreactivity or affinity toward the substrate 302. By way of example andnot limitation, the amphiphilic material may include at least one of achloroalkyl, a chloroalkene, a 1-alkene and a 1-alkyne. As anothernon-limiting example, the blocking material 308 may include a resistmaterial or a polymer material, such as a photoresist material,polymethylglutarimide (PMGI), polyethylene, polystyrene, polyurethane,poly(methyl methacrylate) (PMMA), phenol formaldehyde, a novolacpolycresole, a polyimide and a fluoro resin. The blocking material 308may be formed over the substrate 302 using conventional deposition andpattering techniques, which are not described in detail herein. Theblocking material 308 may be formed by exposing the surface of the workpiece 300 (i.e., exposed surfaces of the substrate 302) to theamphiphilic material under conditions such that the amphiphilic materialselectively interacts with exposed regions of the substrate 302. As anon-limiting example, the work piece 300 may be formed from silicon andthe blocking material 308 may be formed by exposing the surface of thework piece 300 to 1-octadecene so that the 1-octadecene reacts with theexposed surfaces of the substrate 302 to form a self-assembled monolayerover the substrate 302. As another non-limiting example, the work piece300 may be formed from silicon and the blocking material 308 may beformed by exposing the surface of the work piece 300 tobis(trimethylsilyl)telluride so that the bis(trimethylsilyl)telluridereacts with the exposed surfaces of the substrate 302 to form theblocking material 308 over the substrate 302. Optionally, the surface ofthe substrate 302 may be prepared by at least one of cleaning andetching prior to depositing the blocking material 308 thereon.

An opening 306 may be formed in the blocking material 308 to expose asurface of the substrate 302 using methods known in the art, such as,conventional lithographic techniques. For simplicity, the blockingmaterial 308 shown in FIG. 3A includes a single opening 306. However,the blocking material 308 may include any number of openings 306.

An ALD material 310 may be formed on the exposed surface of thesubstrate 302 using the ALD process 100 described with respect toFIG. 1. A first thickness D3 of the ALD material 310 may be formed onthe exposed surface of the substrate 302 using at least one ALD cycle102 (FIG. 1). During the ALD cycle(s) 102, the blocking material 308 mayprevent deposition of the ALD material 310 over surfaces of thesubstrate 302 underlying the blocking material 308. For example, betweenabout 5 ALD cycles 102 and about 100 ALD cycles 102 and, moreparticularly, about 75 ALD cycles 102, may be performed to form thefirst thickness D3 of the ALD material 310 on the work piece 300. By wayof non-limiting example, the blocking material 308 may be formed from1-octadecene, the ALD material 310 may comprise platinum and from about50 ALD cycles 102 to about 75 ALD cycles 102 may be performed so thatthe first thickness D3 of the platinum is less than or equal to about 25Å. As another non-limiting example, the blocking material 308 may beformed from a polymer material, the ALD material 310 may compriseplatinum and from about 10 ALD cycles 102 to about 20 ALD cycles 102 maybe performed so that the first thickness D3 of the platinum is less thanor equal to about 25 Å. During the ALD process, the blocking material308 may become damaged or degraded and the reactivity of the surface ofthe substrate 302 toward the blocking material 308 may be diminished. Asthe blocking material 308 is damaged or degraded during the ALD cycle(s)102, the ALD material 310 may be undesirably deposited on surfaces ofthe substrate 302 previously covered by the blocking material 308. Thus,the first thickness D3 of the ALD material 310 may be limited by thenumber of the ALD cycles 102 that may be performed before the blockingmaterial 308 is damaged or degraded.

The blocking material 308 may be restored or coated by optionallyperforming the surface treatment 106 (FIG. 1) and the activationtreatment 104 (FIG. 1) during the ALD process 100 (FIG. 1). To restorereactivity of the surface of the substrate 302 toward the blockingmaterial 308, the activation treatment 104 may, optionally, beperformed. As a non-limiting example, the substrate 302 may be formedfrom silicon and an oxidizing agent, such as oxygen, ozone, or water,may be introduced to the work piece 300 to increase surface reactivityof the silicon. In some embodiments, the activation treatment 104 may beperformed in situ by introducing, for example, the oxidizing agent tothe work piece 300 in the same reaction chamber in which the ALD processis performed. In other embodiments, the work piece 300 may be removedfrom the reaction chamber and the activation treatment 104 may beperformed ex situ.

After restoring surface reactivity of the substrate 302 using theoptional activation treatment 104, the surface treatment 106 may beperformed to restore or to coat the blocking material 308 overlying thesubstrate 302. In some embodiments, the surface treatment 106 mayinclude exposing the work piece 300 to an organic material that reactswith exposed surfaces of the substrate 302 and remaining portions of theblocking material 308 to restore the blocking material 308. For example,the blocking material 308 may be formed from the amphiphilic material orthe resist material and an organic material may be introduced to exposedsurfaces of the substrate 302 and remaining portions of the blockingmaterial 308 to restore the blocking material 308.

In other embodiments, the surface treatment 106 may include exposing thework piece 300 to a polymer material that polymerizes on exposedsurfaces of the substrate 302 and/or remaining portions of the blockingmaterial 308 to form a coating 312 (shown in broken lines) over theblocking material 308. The ALD material 310 may inhibit deposition ofthe polymer material over the ALD material 310 such that the coating 312does not form over the ALD material 310. For example, the polymermaterial may include a parylene, such as a substituted[2.2]paracyclophane, and the blocking material 308 may be restored byexposing the blocking material 308 to the organic material in asublimated or vapor state. The ALD material 310 may include a materialthat inhibits deposition of the polymer material, such as, platinum,gold, silver, nickel, copper, iridium, tungsten, thallium and titanium.For example, the polymer material may be sublimated at a temperature offrom about 75° C. to about 150° C. and introduced into the reactionchamber such that the polymer material polymerizes on the exposedsurfaces of the substrate 302 and/or remaining portions of the blockingmaterial 308 without polymerizing on the ALD material 310 to form thecoating 312. The coating 312 may protect the blocking material 308 fromfurther damage or degradation or may replace degraded or damaged regionsof the blocking material 308.

As a non-limiting example, the surface treatment 106 (FIG. 1) may beperformed in situ by introducing the organic material or the polymermaterial to the exposed surfaces of the substrate 302 and the remainingportions of the blocking material 308 in the same reaction chamber usedto perform the ALD cycle(s) 102 (FIG. 1). As another non-limitingexample, the work piece 300 may be removed from the reaction chamber andthe surface treatment 106 may be performed by depositing the organicmaterial or the polymer material over the exposed regions of thesubstrate 302 and the remaining portions of the blocking material 308using, for example, a conventional chemical vapor deposition (CVD)process. For example, the blocking material 308 may include 1-octadeceneand the work piece 300 may be exposed to a vapor containing1-octadecene, so that the 1-octadecene reacts with the exposed regionsof the substrate 302 and the remaining portions of the blocking material308. As the 1-octadecene in the vapor contacts remaining portions of theblocking material 308, a self-assembled monolayer of the 1-octadecenemay form over the exposed regions of the substrate 302 and the remainingportions of the blocking material 308. As another non-limiting example,the blocking material 308 may include 1-octadecene and the work piece300 may be exposed to a vapor containing a substituted parylene so thatthe substituted parylene polymerizes over exposed surfaces of thesubstrate 302 and the remaining portions of the blocking material 308without depositing on the ALD material 310. As the substituted parylenein the vapor contacts remaining portions of the blocking material 308,the substituted parylene may polymerize over the exposed regions of thesubstrate 302 and the remaining portions of the blocking material 308 toform the coating 312 thereover. As indicated by arrow 108 (FIG. 1), theactivation treatment 104 and the surface treatment 106 may be repeatedany number of times in order to restore or to coat the blocking material308 overlying the substrate 302.

After performing the surface treatment 106 to regenerate or coat theblocking material 308, at least another ALD cycle 102 (FIG. 1) may beperformed, as indicated by arrow 110, to form a second thickness D4 ofthe ALD material 310 over the first thickness D3 of the ALD material310. The ALD cycle(s) 102, the surface treatment 106 and, optionally,the activation treatment 104 may be repeated to form a desired thicknessof the ALD material 310. By periodically performing the surfacetreatment 106 and, optionally, performing the activation treatment 104between the ALD cycles 102, an increased thickness of the ALD material310 may be formed in comparison to that formed using conventionalarea-selective ALD processes. For simplicity, as illustrated in FIG. 3B,the ALD material 310 includes two thicknesses (i.e., the first andsecond thicknesses D3 and D4). However, any number of thicknesses of theALD material 310 may be formed using the disclosed methods.

CONCLUSION

In some embodiments, the present disclosure includes methods ofselectively forming a material. The methods may include forming ablocking material over portions of a substrate, at least one surface ofthe substrate exposed to the blocking material, forming a firstthickness of at least one material by atomic layer deposition on the atleast one exposed surface of the substrate and exposing the blockingmaterial to at least one organic material to restore the blockingmaterial.

In additional embodiments, the methods of selectively forming a materialmay include forming a plurality of recesses in a material overlying asubstrate, each of the plurality of recesses exposing a surface of thesubstrate, forming a blocking material over exposed surfaces of thematerial, forming a portion of at least one material on the surface ofthe substrate by atomic layer deposition and exposing the blockingmaterial to an organic material to restore the blocking material.

In yet further embodiments, the methods of selectively forming amaterial include introducing at least one precursor to a substrate toform a material on at least one surface of the substrate exposed betweenportions of a blocking material, exposing the substrate to an inert gasto remove the at least one precursor and introducing at least oneorganic material to form the at least one organic material on at leastone of remaining portions of the blocking material and surfaces of amaterial on the substrate.

Additional embodiments of the present invention include a semiconductorstructure that includes a material overlying a silicon substrate andhaving a plurality of recesses therein, each of the plurality ofrecesses exposing a surface of the silicon substrate and at least onematerial comprising a material formed by atomic layer deposition, the atleast one material overlying the surface of the silicon substrate andhaving a thickness of greater than about 25Å.

While the invention may be susceptible to various modifications andalternative forms in implementation thereof, specific embodiments havebeen shown by way of example in the drawings and have been described indetail herein. However, it should be understood that the invention isnot limited to the particular forms disclosed. Rather, the inventionencompasses all modifications, variations and alternatives fallingwithin the scope of the invention as defined by the following appendedclaims and their legal equivalents.

What is claimed is:
 1. A semiconductor structure comprising: anintermediate material overlying a substrate, the intermediate materialcomprising at least one recess therethrough and exposing top surfaces ofthe substrate; a blocking material over sidewalls of the intermediatematerial but not over the top surfaces of the substrate; a first metalmaterial over the top surfaces of the substrate but not over theblocking material; and a parylene coating over the blocking material butnot over the first metal material.
 2. The semiconductor structure ofclaim 1, wherein the first metal material comprises at least onematerial selected from the group consisting of platinum, gold, silver,nickel, copper, iridium, tungsten, thallium, and titanium.
 3. Thesemiconductor structure of claim 1, further comprising a second metalmaterial over the first metal material but not over the parylenecoating.
 4. The semiconductor structure of claim 1, wherein the secondmetal materials comprises at least one material selected from the groupconsisting of platinum, gold, silver, nickel, copper, iridium, tungsten,thallium, and titanium.
 5. The semiconductor structure of claim 1,wherein the blocking material comprises a material selected from thegroup consisting of a resist material, a polymeric material, and anamphiphilic material.
 6. The semiconductor structure of claim 1, whereinthe blocking material comprises at least one of a chloroalkyl compound,a chloroalkene, a 1-alkene, and a 1-alkyne.
 7. The semiconductorstructure of claim 1, wherein the blocking material comprises at leastone of a photoresist material, polymethylglutarimide (PMGI),polyethylene, polystyrene, polyurethane, poly(methyl methacrylate)(PMMA), phenol formaldehyde, a novolac polycresole, a polyimide, and afluoro resin.
 8. The semiconductor structure of claim 1, wherein theblocking material comprises at least one of octadecyltrichlorosilane(ODTS), dodecyltrichlorosilane, methylchlorosilane, andtridecafluoro-1,1,2,2-tetrahydrooctyltrichloro-silane (FOTS).
 9. Thesemiconductor structure of claim 1, wherein the parylene coatingcomprises a substituted [2.2]paracyclophane.
 10. The semiconductorstructure of claim 3, further comprising a third metal material over thesecond metal material but not over the parylene coating.
 11. Thesemiconductor structure of claim 10, wherein each of the first, secondand third metal materials comprises the same material.
 12. A method ofselectively forming a material, the method comprising: forming a firstmaterial by atomic layer deposition on at least one surface of asubstrate exposed between portions of a blocking material; forming aparylene coating over the blocking material without forming the parylenecoating on the first material; and forming a second material by atomiclayer deposition on the first material without forming the secondmaterial on the parylene coating.
 13. The method of claim 12, whereinforming a first material by atomic layer deposition on at least onesurface of a substrate exposed between portions of a blocking materialcomprises forming a material selected from the group consisting ofplatinum, hafnium oxide, copper, titanium dioxide, nickel, molybdenum,zinc sulfide, gallium arsenide, indium phosphide, tin dioxide, magnesiumoxide, nickel oxide, iridium, ruthenium, iridium dioxide, rutheniumoxide, barium strontium titanate (Ba_(1-x)Sr_(x)TiO₃,), lead zirconatetitanate ((Pb[Zr_(x)Ti_(1-x)]O₃), germanium-antimony-tellurium(Ge₂Sb₂Te₂), germanium sulfide, and copper telluride.
 14. The method ofclaim 12, wherein forming a first material by atomic layer deposition onat least one surface of a substrate exposed between portions of ablocking material comprises forming a material configured to inhibitformation of a parylene coating thereon.
 15. The method of claim 14,wherein forming a material configured to inhibit formation of a parylenecoating thereon comprises forming a material selected from the groupconsisting of platinum, gold, silver, nickel, copper, iridium, tungsten,tantalum, and titanium.
 16. The method of claim 12, wherein forming asecond material by atomic layer deposition on the first material withoutforming the second material on the parylene coating comprises formingthe second material comprising the same material as the first material.17. The method of claim 12, wherein forming a second material by atomiclayer deposition on the first material without forming the secondmaterial on the parylene coating comprises forming the second materialcomprising a different material from the first material.
 18. The methodof claim 12, wherein forming a parylene coating over the blockingmaterial without forming the parylene coating on the first materialcomprises exposing the blocking material to a parylene in a sublimed orvapor state after forming the first material by atomic layer deposition.19. The method of claim 12, further comprising forming a third materialby atomic layer deposition on the second material without forming thethird material on the parylene coating, wherein the third materialcomprises the same material as the second material.